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Why you have to modulate the signal?

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βˆ™ 2007-12-05 12:37:16

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Sometimes we have to send low frequency information, like the tone of the voice of someone talking on a telephone, over a specific channel that only permits a specific high frequency, such as radio frequencies (RF). So how do we do that? One simple, cost effective, and bandwidth efficient method is to change, or modulate, a known RF signal a certain way. Some common ways of modulating such a high frequency signal are Amplitude Modulation and Frequency Modulation. Each of these modulation techniques has its own advantages and disadvantages and are therefore more useful in certain applications.

2007-12-05 12:37:16
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Modems how did it get its name?

Modem derived from the words modulate (convert a digital signal into an analog signal ) and demodulate (convert an analog signal into a digital signal) which describe its function.

Why is it necessary to modulate the picture and sound signals before transmission?

Modulation can be thought of as the addition of what we want to transmit to the carrier signal. We say that we modulate (add information or intelligence to) that carrier, so given that, it is fairly easy to see that we are required to modulate the carrier before we transmit that carrier signal. Without any modulation, the carrier is the only thing transmitted. We'd see only that carrier if we intercepted or received the signal.

What does modulate mean?

Modulate can mean a few different things. It can refer to altering a frequency with a second lower signal, varying the strengths and tones of a voice, or exerting control or influence on something.

How do you use modulate in a sentence?

The word 'modulate' is a verb, a word meaning to change or vary the pitch, intensity, or tone; to adjust to a certain degree; to vary an electromagnetic wave for the transmission of a radio signal; a word for an action.Example sentences:You modulate your voice in order to emphasize the main points.Is there anything in the medicine cabinet to modulate a fever?

Multiple choice question answer of AM modulation?

amplitude modulation is where we modulate our signal with a carrier signal amplitude changes but frequency remains constant in amplitude modulation

Why modulation is required to modulate a signal before transmission?

The baseband signal will not propagate far enough on its own.Multiple baseband signals would interfere, preventing more than one signal from being sent.

Is modulate a verb?

yes modulate is indeeda verb

What is the past tense of modulate?

The past tense of modulate is modulated.

Is a modem an input only?

Modem is short for MODulate/DEModulate. It modulates a signal to send across a serial wire, and demodulates the signal that comes back.In other words, a modem is both an input AND an output device.

What is the need of modulation?

we modulate audio signal due to following reasons: -audio is a low frequency signal that cannot travel longer distance due to low energy -if we transmit the signal without modulation then the height of antenna will be of the order of several thousand kilometers that is impractical

What is an carrier amplifier?

It is a direct-current amplifier in which the dc input signal is filtered by a low-pass filter, then used to modulate a carrier so it can be amplified conventionally as an alternating-current signal; the amplified dc output is obtained by rectifying and filtering the rectified carrier signal.

What is a modems purpose?

1. To MODULATE (convert) the digital signals from a computer into analogue signal to enable it to be carried through the telephone line. 2. To DEMODULATE (convert back) analogue signals from a telephone line into digital signal to be used in computer.

Why it is necessary to modulate the picture and sound signal before transmission?

To avoiding the noise signal effect.Because the modulation is a technic which providing a high characteristic to transmitting the signal on long or short distance.Because the modulated signal received as high bandwidth,high performance of received signal and the modulation Technic is provide a less hight of antenna in wireless transmission which is expressed in the term :(hight of antenna=λ/4).

How do you modulate from E flat major to G flat major?

Modulate to E flat minor first!

Use modulate in a sentence?

It means to adjust or regulate. Here are some sentences.Modulate your voice when you are inside the house!They must modulate the frequency so that the machine will work properly.The organist should modulate to another key because the singer can't hit all the notes.

How did the modem get its name?

To send digital across an analog wire the signal is first laid on top of an analog signal. The process is called "modulation". It's the same thing that's done with television and radio, it's just a different type of signal.The modulated signal is sent across the wire and the MODEM at the other end receives the signal and decodes it.The process is called, "MOdulate, DEModulate, or more simply, MODEM.

What are the differences between analog and digital modulation?

There is no modulation of a Digital Circuit.Modulation is placing information onto an analog circuit to transport thatinformation to a distant location to be decoded/demodulated.Having said that, you can modulate a digital signal in dozens of ways,(Modem) and you can also modulate an analog signal dozens of ways(AM Radio Station, CB Radio, Walkie Talkie, FM Rock Station).NoteWhat this question may really be asking about is something like:"What are the differences between using an analog signal and a digital signal when you want to encode some information for transmission?"so that has now been posted as a separate question.

Why inTV broadcasting video signal is trancemitted in AM but audio signal is in FM?

AM was used for the video signal because components to transmit and receive the video signal (tubes, originally) were not available that could modulate the frequency fast enough for the amount of information required for a video signal. The VHF band, where most of television broadcasts resided until the the adoption of Digital Television (DTV) was also being used for FM audio broadcasts.

What device allows data to be sent from computer to computer over a telephone line?

A modem allows data to be transferred over a telephone line. It is a combination of MOdulate - DEModulate. One device modulates a digital signal from the computer into an analog signal for the telephone line, then the other device demodulates the signal back into digital for the receiving computer.

How do you modulate from E-flat major to F?

If you are in E-flat major, firstly modulate to the dominant key of E-flat (which is B-flat major) and from there you can modulate to the fifth in B-flat major which is F major.

How does a ham radio work?

The process is very complicated, but I can simplify it here. A signal starts as a wave in the oscillator of the radio. You speak into the microphone, and this produces another wave at your voice frequency. These two signals go into the modulator, which uses the voice signal to encode the wave from the oscillator, or modulate it. This signal is sent out of the antenna. The receiver is like a transmitter in reverse (obviously), that decodes it, and sends the decoded signal into the speaker.

How do you modulate in matlab without using matlab tools?

You would have to write your own code for a modulation (Matlab has a convolution function not in the tools), otherwise you can use its built in function in the signal processing toolbox.

Whatis the function of modem?

MOdulate/DEModulate. It converts digital computer signals into analog ones for transmission over analog telephone lines, and then converts the signal back into digital on the other end.

Why modulation is required?

modulation is required from energetic viewpoint: you can't directly send electrical oscillations of sound frequency! You have to modulate - to "seat sound signal" on high frequency electromagnetic oscillations & send!

Modulate and demodulate gives you what?